IF a Receiver is covered up can he

My guess would be no he cannot. A covered up receiver is no different from an o-lineman other than wearing an eligible number.

If he's covered he's not eligible, though.

Additional thought: CYFL's answer is correct. In order to be covered up, you must be aligned on the LOS and usually occurs when a player aligns in a standard TE position and the wide out on his side aligns himself on the LOS as well. The covered up player then becomes nothing more than an offensive lineman according to the rules, and becomes inelgible to touch a pass and is not elgible to go any further downfield than the normal 3 yds alloted any OL.

Coach Easton

Clarification NCAA rules: Ineligable recievers (covered) are eligable to catch BACKWARDS passes behind the LOS -- eg Bubble Screens

according to ncaa rules (which we play in texas) an ineligible player can receive a backwards lateral. we really like to run X-over, sprint to the X-over side, then throw the "tackle screen" back to the opposite side. it's a lateral & is great inside the 25 yard line if you got a tackle that's not a big gob of goo.